Effects of hyposmolar solutions on membrane currents of hippocampal interneurons and mossy cells in vitro.
Whole cell voltage-clamp recordings in rat hippocampal slices were used to investigate the effect of changes in extracellular osmolarity on voltage-activated potassium currents. Currents were evoked from oriens/alveus (O/A) interneurons, hilar interneurons, and mossy cells. Hyposmolar external solutions produced a significant potentiation of K+ current recorded from O/A and hilar interneurons, but not from mossy cells. Hyposmolar solutions also dramatically potentiated the spontaneous excitatory postsynaptic currents recorded from mossy cells. These results suggest that hippocampal excitability can be modulated by the complex actions exerted by changes in extracellular osmolarity.
Baraban
S C
SC
Department of Neurological Surgery, University of Washington, Seattle, Washington 98195, USA.
Schwartzkroin
P A
PA
D000818:Animals; D002478:Cells, Cultured; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D006624:Hippocampus / Q000166:cytology*; D007038:Hypotonic Solutions / Q000494:pharmacology*; D007395:Interneurons / Q000187:drug effects*; D017136:Ion Transport / Q000187:drug effects; D019599:Mossy Fibers, Hippocampal / Q000187:drug effects*; D009474:Neurons / Q000187:drug effects*; D009994:Osmolar Concentration; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D007038:Hypotonic Solutions; D011188:Potassium